Electrocatalytic and energy storage performance of bio-derived sulphur-nitrogen-doped carbon

Sulphur and nitrogen-rich carbon layers (S/N-CLs) have been derived successfully via a simple calcination for high energy applications including supercapacitor and electrocatalytic hydrogen evolution reaction (HER). The flexible working electrode was fabricated using thoroughly analyzed S/N-CLs composite as an active electrode energy material for supercapacitor and HER. The S/N-CLs composite shows a higher specific capacitance of 266 F g−1 at a current density of 0.5 A g−1 and a satisfied cycling stability with 84% capacitance retention even after 5000 cycles of galvanostatic charge-discharge. On the other hand, the synthesized S/N-CLs composite was used as an electrocatalyst for HER and it exhibits an excellent HER performance with an onset overpotential of −75 mV, and a Tafel slope of 73 mV dec−1 in 0.5 M H2SO4 aqueous electrolyte. Also, the S/N-CLs composite displayed good stability and strong durability. The high electrocatalytic activity and stability of S/N-CLs composite toward HER due to the active site of a compound which may originate from the heteroatom-functional groups including N and S in the carbon structure. Overall, the high-performance supercapacitors and enhancing HER based on heteroatom-doped carbon structures could be promising in replacing traditional supercapacitors for many electronic devices and electrocatalyst for HER.